1. Field of the Invention
The present invention relates to electrical connectors and, more particularly, to card edge connectors.
2. Prior Art
In the electrical arts it is a common practice to use a card edge connector to mechanically and electrically couple a mother printed circuit board with a daughter printed circuit board as of the vertical edge card variety. In such a practice, there has been an evolution towards placing electrical contacts closer and closer together while maintaining a high, constant stress between the electrical contacts and the areas to be contacted on the daughter board. In placing the contacts closer together, the width of each contact must decrease. This, in turn, makes it much more difficult to keep the proper contact stress between the contact and the areas to be contacted while also assuring proper alignment between the two upon insertion of the card edge into the connector. There has also developed a special type of connector which is known in the art as a bi-level connector; i.e.: a connector having two types of contacts that make contact with a daughter printed circuit board in two locations or at two levels. The two types of contacts are generally arranged in two opposing rows with a card edge receiving slot therebetween.
The high density card edge connector in the past encountered a problem in regard to the amount of force that was necessary to insert the edge of the daughter printed circuit board into the connector because each contact is a spring contact and it must be at least partially moved by the card edge and because there are more contacts in the high density connectors. The bi-level connector alleviated this problem, to a degree, by allowing for a two step engagement of the card edge with the contacts; the first step being the displacement of the upper first type of contacts and the second step being the displacement of the lower second types of contacts.
Another type of card edge connector known in the art is a zero insertion force (ZIF) connector that uses levers to move contacts into and out of a card receiving slot. One such connector is shown in U.S. Pat. No. 4,636,021. However, these types of connectors do not allow for the contacts to scrub against the daughter board to insure proper electrical contact therewith. U.S. Pat. No. 3,970,353 shows a clip for locking a daughter board in a connector. And U.S. Pat. No. 4,869,672 discloses a dual purpose card edge connector.
As illustrated by a great number of prior patents, as well as commercial devices, efforts are continuously being made in an attempt to improve connectors and their contacts to render them more efficient, effective and economical. None of these previous efforts, however, provides the benefits attendant with the present invention. The present invention achieves its intended purposes, objects and advantages over the prior art devices through a new, useful and unobvious combination of component elements, with the use of a negligible number of functioning parts and at a reasonable cost to manufacture.